code: def test_stack_column(self, extracts, column_names, expected_result):
      result = object_detection_format.stack_labels(
          extracts, column_names
      )
      np.testing.assert_allclose(result, expected_result)
  
file_path: model-analysis/tensorflow_model_analysis/metrics/preprocessors/utils/object_detection_format_test.py
imports: from absl.testing import absltest
  from absl.testing import parameterized
  import numpy
  from tensorflow_model_analysis import constants
  from tensorflow_model_analysis.metrics.preprocessors.utils import object_detection_format
  from tensorflow_model_analysis.utils import util
label_desc: Use image node_id 1 for calling the ObjectDetectionFormatTest obj's underlying member method code with example usage: obj.test_stack_column(extracts, column_names, expected_result) without return types